The sowder library ranking scale
1 - Pile of books in boxes or in random order on shelves. Probably not being used. No budget.
3 - Selected and on shelves in order by a (probably local) classification scheme. Manual circulation
5 - Searcheable computer list of holdings; Circulation to patrons
7 - Computerized catalog and circulation, serials, ILL?
9 - Integrated Library System (ILS) with OPAC, Circulation, ILL, Acquistions, Serials
10 - Nirvana?
Open source library systems
KOHA (http://www.liblime.com/demos) List of demo and live websites
Evergreen (http://demo.gapines.org/)Demo only but note that many libraries run this. Noteably in Georgia but other places as well (including Michigan).
Scriblio (library catalog) (http://www.plymouth.edu/library/opac)Demo. Based on blogging software
Scriblio (digital image collection) (http://beyondbrownpaper.plymouth.edu/browse)
Library Technology Reports, v43 no 3, May/June 2007 "Open Source Software for Libraries"
Library Technology Reports, v40 no 1, January/February 2004 "Integrated Library Software: A Guide to Multiuser, Multifunction Systems"
Somewhat dated but does have the major players listed with descriptions
Library Technology Reports, v43 no 4, July/August 2007 "Next-Generation Library Catalogs"